Giant double-ring radio galaxy found halfway across the universe

Giant double-ring radio galaxy found halfway across the universe
by Sophie Jenkins
London UK (SPX) Oct 06, 2025

Astronomers have discovered the most distant and powerful odd radio circle (ORC) ever observed, revealing a rare cosmic structure nearly halfway across the universe. The newly identified source, RAD J131346.9+500320, lies at a redshift of about 0.94 - when the universe was roughly half its present age.

These enormous, faint rings of magnetised plasma emit only in the radio band and typically span 10 to 20 times the diameter of the Milky Way. The new object, which displays two intersecting rings, is only the second known example of this kind. Researchers believe such structures may form from superwind outflows from spiral host galaxies rather than from black hole or galaxy merger shockwaves, as previously suggested.

The discovery, published in Monthly Notices of the Royal Astronomical Society, was made by researchers at the University of Mumbai using the RAD@home Astronomy Collaboratory citizen science network and the Low-Frequency Array (LOFAR), the world's most sensitive low-frequency radio telescope.

"ORCs are among the most bizarre and beautiful cosmic structures we've ever seen - and they may hold vital clues about how galaxies and black holes co-evolve," said Dr Ananda Hota, founder of RAD@home. "This work shows how professional astronomers and citizen scientists together can push the boundaries of scientific discovery."

LOFAR's vast network of antennas across Europe acts as a single giant interferometer, allowing astronomers to peer deep into cosmic history at low radio frequencies. Using these observations, the RAD@home team also identified two other extraordinary radio galaxies - RAD J122622.6+640622 and RAD J142004.0+621715 - each stretching over a million light-years and shaped by interactions between black hole jets and surrounding hot plasma in dense galaxy clusters.

"These discoveries show that ORCs and radio rings are not isolated curiosities - they are part of a broader family of exotic plasma structures shaped by black hole jets, winds, and their environments," said co-author Dr Pratik Dabhade of the National Centre for Nuclear Research in Warsaw, Poland.

Future instruments such as the Square Kilometre Array (SKA) and major optical surveys like DESI and the Vera C. Rubin Observatory's LSST are expected to reveal many more ORCs, shedding light on how these colossal radio rings form and evolve.

Research Report:RAD@home discovery of extragalactic radio rings and odd radio circles: clues to their origins